1. Field
The following description relates to an address translation apparatus and method for effectively supporting a chip fault-tolerance function in a memory.
2. Description of Related Art
Recently, technologies of effectively providing and storing a large amount of information have been actively conducted.
A Redundant Array of Inexpensive Disks (RAID), one of a number of information storage schemes, may divide and redundantly store data over multiple hard disks. There are various schemes for dividing data, and the data dividing scheme is referred to as a level. A reliability of a storage device or a throughput of the storage device may increase depending on the level.
Specifically, the RAID may combine multiple disks into a single unit and may enable the multiple disks to perform as a single logical disk using either a hardware-based method or a software-based method. The hardware-based method may enable the multiple disks to be shown, to an operation system, as the single disk, and the software-based method may be embodied in an operation system and may enable the multiple disks to be shown, to the user, as the singe disk.
The RAID may store information using a Flash Translation layer (FTL) that is one of a number of storage schemes, because an overwrite operation cannot be performed in a write area of a flash memory before an erase operation is performed, a read operation and the write operation may be performed based on a page unit, and the erase operation may be performed based on a block unit that is greater than the page unit.
However, a conventional storage device does not include the erase operation and needs to perform the overwrite operation, and thus, the FTL may have a mapping table between a logical address and a physical address of the flash memory, preventing the restrictions of the flash memory from being revealed to an outside of the storage device.
As an example, when data is overwritten in the same logical address, the FTL may store the data in a page of another physical address without performing the erase operation, and may update a mapping between the logical address and the other physical address in the mapping table.
Accordingly, the FTL may enable the data to be stored in a different physical location that is different from a storage address shown from the outside the device, enabling the device to follow the restrictions of a flash memory and to be performed as the conventional storage device.
The FTL may be classified, based on an address translation unit, into a page (write) unit address translation and a block (erase) unit address translation. The page unit address translation precisely performs address translation and may give a high performance, while a manufacturing cost increases since a size of the address translation table increases.
As an example, a storage device constituted by a flash, such as a solid-state Drive (SSD), may include the FTL and the RAID layer to have a fault-tolerance function in a chip level in the same manner as the RAID. However, the RAID may not provide a high performance with respect to writing a small amount of data.